The present invention is directed to a hand-held motor-driven extruding device for dispensing plastic substances, such as sealing compounds, bonding agents, putty and the like with a container for the plastic substance and a piston movable back and forth along the length of the container. The motor drive is arranged in a drive housing equipped with a handle.
If the plastic substance is packaged in a cartridge with a diameter corresponding to that of the piston, then the cartridge can be inserted into a trough-shaped, semi-cylindrical holder when the piston is fully retracted. The invention can also be used with a cylindrical holder so that the plastic substance packaged in a foil sheath can be positioned within the holder forwardly of the retracted piston.
Since the operation of a hand-held extruding device can be very tiring and causes the operator to discontinue the extruding operation while some of the plastic substance remains in the cartridge, manually operated extruding devices using compressed air or an electromotor drive were developed. The compressed air-driven extruding devices require a compressor at the construction site and it is often difficult to accommodate a compressor, particularly when adhering roof coverings. Further, the required hoses frequently become fouled by the plastic substance being used and tend to become blocked resulting in a considerable amount of work in cleaning such devices.
Motor-driven hand operated extruding devices with a worm drive for the piston have the disadvantage that the piston rod extends out of the drive housing when the piston is retracted and the rod can easily be bent due to rough handling. If the piston rod becomes bent, the device can no longer be used. To avoid the use of power lines, it has been known to use manually operated extruding devices without cables which are powered by rechargeable batteries.